The benefits of antiretroviral therapy (ART) can only be achieved through timely HIV diagnosis, successful linkage to care, and treatment initiation. In South Africa, however, only a fraction of those newly diagnosed with HIV enter HIV care. The period after HIV testing but prior to ART initiation represents a time of very high mortality, fueled by the tuberculosis (TB) epidemic, and therefore a time when improving access to TB screening and HIV care would be of substantial benefit. Though TB is the leading cause death among those with HIV in sub-Saharan Africa, less than one-third of HIV-infected South Africans have been screened for TB. Efforts are urgently needed to implement and evaluate strategies that improve early diagnosis and linkage to HIV and TB care, and to consider such strategies in the context of constrained healthcare resources. We propose two specific aims. The first aim is to conduct a randomized controlled trial to establish the efficacy of a health system navigator intervention in improving linkage to HIV and TB care among newly diagnosed HIV-infected outpatients in Durban, South Africa. Using Andersen's model of health service utilization as a theoretical framework, we will provide a health system navigator to help patients identify and overcome barriers to care and we will examine the intersection of contextual and patient-level factors that affect linkage to care. The second aim is to evaluate the cost and cost-effectiveness of this intervention for promoting linkage to HIV and TB care at the time of HIV screening. The 2010 Trans-NIH Plan for HIV-related research prioritizes the assessment of outcomes related to TB and HIV care integration on survival, quality of care, and cost, as well as the impact of different approaches for testing, linkage, and retention in care in improving outcomes of HIV disease. The proposed study will address several of these important issues through collaboration among medical, behavioral and cost- effectiveness experts working in the US and the South African province with the highest prevalence of HIV and TB. The results will inform HIV and TB care in South Africa and in other resource-limited settings.